Economic Evaluation of Andexanet Versus Prothrombin Complex Concentrate for Reversal of Factor Xa-Associated Intracranial Hemorrhage.

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Request for an Andexxa Value Analysis.

This perspective is a formal request to the American College of Cardiology and American Heart Association (ACC/AHA) to perform a value analysis on andexanet (Andexxa) similar to what was completed for the PCSK9 inhibitors in the 2018 ACC/AHA Blood Cholesterol guidelines. Based on the safety and efficacy concerns of andexanet alfa, a value statement in and or as an addendum to society guidelines is vital considering the high cost of therapy. In this era of ever-increasing health care costs, every clinician, health system, national society, insurer, and pharmaceutical company should work to be good stewards of our society's resources.

Cost comparison of andexanet versus prothrombin complex concentrates for direct factor Xa inhibitor reversal after hemorrhage.

Andexanet-alpha is a specific reversal agent for direct factor Xa inhibitors (dFXaI). We aimed to project utilization rates and cost of andexanet for reversal of dFXaI-related major hemorrhage compared to 4-factor prothrombin complex concentrates (4F-PCC). A retrospective, multicenter review was conducted between 1/1/2014 and 7/15/2018 of patients who received 4F-PCC for reversal of dFXaI-related life-threatening hemorrhages. Total hospital reimbursements/patient were calculated based on national average MS-DRG payments adjusting for Medicare discounts. The projected cost for andexanet (based on dose and insurance) and % reimbursement/patient was compared to the actual cost of 4F-PCC. Hemostasis at 24 h (excellent/good vs. poor) and 30-day thrombotic complications were assessed. Of 126 patients who received 4F-PCC to reverse dFXaI, 46 (~ 10 per-year) met inclusion criteria. The median projected cost of andexanet was $22,120/patient, compared to $5670/patient for 4F-PCC (P < 0.001). The median hospital reimbursement was $11,492/hospitalization. The projected cost of andexanet alone would exceed the entire hospital reimbursement in 74% of patients by a median of $7604, while 4F-PCC cost exceeded the total hospital payments in 7% of patients in the same cohort (P < 0.001). Hemostasis was excellent/good in 72% of patients post-4F-PCC, compared to 82% in andexanet trials. Thromboembolic events occurred in 4% of patients following 4F-PCC versus 10% in andexanet trials. The projected cost of andexanet would exceed the national average hospital reimbursement/patient in nearly 75% of patients by over $7500/hospitalization. 4F-PCC was significantly less expensive, had lower rates of thrombosis, but also lower rates of good/excellent hemostasis compared to published data for andexanet.

Emergent reversal of oral factor Xa inhibitors with four-factor prothrombin complex concentrate.

BACKGROUND: Controversy exists regarding first-line use of the recently approved reversal agent andexanet alfa due to limitations of the ANEXXA-4 study, thrombotic risks, and high medication acquisition cost. The purpose of this study was to evaluate the safety and effectiveness of 4F-PCC for the reversal of emergent oral fXa inhibitor-related bleeding. Furthermore, we aimed to evaluate a subgroup using strict ANNEXA-4 patient selection criteria. METHODS: This was a retrospective study conducted utilizing chart review of adult patients that received 4F-PCC for oral fXa inhibitor-related bleeding. The primary endpoint was the rate of clinical success defined as achieving excellent or good hemostatic effectiveness following the administration of 4F-PCC. Secondary endpoints included in-hospital mortality and arterial/venous thromboembolism, and cost compared with andexanet alfa. RESULTS: A total of 119 patients were included, with 83 patients in the ANNEXA-4 criteria subgroup. Eighty-five of the 119 patients (71%) required reversal due to intracranial bleeding. Prior to reversal, 70 patients (59%) were taking apixaban and 49 patients (41%) were taking rivaroxaban. Clinical success was achieved in 106 of 119 patients (89%) and 74 of 83 patients (90%) in the strict criteria subgroup. Three of 119 patients (2.5%) had a thrombotic event during hospital stay and the overall mortality rate was 13%. The average cost increase of andexanet alfa compared to 4F-PCC would have been $29,500 per patient. CONCLUSIONS: Administration of 4F-PCC for the reversal of oral fXa inhibitors was effective with relatively low thrombotic risk. Further direct prospective comparison of 4F-PCC to andexanet alfa is warranted.

Andexanet Alfa (Andexxa) Formulary Review.

Andexanet alfa, a recombinant modified human "decoy" factor Xa (FXa) protein, is the first and only available antidote approved by the Food and Drug Administration to manage life-threatening or uncontrolled bleeding associated with the anti-Xa agents. It binds to direct and indirect anti-Xa oral anticoagulants with high specificity to reverse their inhibitory effects and restore the activity of FXa. Andexanet alfa is administered via two different dosing regimens, standard and high dose, based on the specific FXa inhibitor, dose, and time since the patient's last dose of FXa inhibitor. The approval for andexanet alfa is supported by data from two phase 3 studies (ANNEXA-A, ANNEXA-R) and preliminary data from the phase 3b/4 ANNEXA-4 trial. The first study found that andexanet alfa rapidly reduced anti-Xa activity by 92%-94% in healthy volunteers taking apixaban or rivaroxaban. The ANNEXA-4 study found that the median anti-Xa activity decreased by 89%-93% in patients with major bleeding taking apixaban or rivaroxaban. However, thrombotic events occurred in 12 of 67 patients (18%) during the 30-day follow-up in ANNEXA-4. Additionally, only 40% of patients had restarted anticoagulation and, in this group, the rate of thrombotic events was 12%. Four patients had a thrombotic event within 3 days after andexanet alfa treatment. The wholesale acquisition cost of the standard dose regimen is $24,750, and the high-dose regimen is $49,500. The estimated annual drug budget of treating 10-100 patients ranges from $248K to $495M. Effective October 1, 2018, Medicare will provide an add-on payment for andexanet alfa of up to $14,063 per qualifying case to Inpatient Prospective Payment System-participating acute care hospitals. In this formulary review for a health system's pharmacy and therapeutics committee, andexanet alfa clinical trials and medication package insert were summarized and, after consulting with clinical experts from our institutions, practical recommendations for use were generated to ensure appropriate and safe use of this agent.